I. Introduction
The highly integrated Electro-hydrostatic actuator (EHA) reduces the heat dissipation area while reducing the volume and mass, which limits its own heat dissipation capacity and causes a part of heat to remain in the closed cavity of the EHA, resulting in a rapid rise in the oil temperature of the EHA system. When the oil temperature rises, the viscosity and density of the oil will change accordingly. The dynamic viscosity μ of oil is a measure of the ability of fluid to resist shear deformation in motion. According to [1], the effect of temperature on μ is large, and the value of μ decreases with increasing temperature. The research of Sun et al [2] shows that the oil temperature of hydraulic system will cause the change of oil viscosity characteristics, thus affecting the performance of hydraulic components and the measurement data accuracy of the test bench, which is equivalent to the variable parameter module of hydraulic components in the process of hydraulic test. This indicates that the temperature of the EHA system affects its own safety. A large number of studies [3]–[6] have shown that under extreme flight conditions, the temperature of EHA oil rises greatly, which affects flight safety. Therefore, the compensation of the influence of oil temperature on the performance of EHA system is an urgent problem to be solved.